Detachable rotary bit



May 18 1926.

c. T. DOUGHERTY DETACHABLE ROTARY BIT Filed Deg. 26, 1923 IN VEN TOR 13 CHARLES 7. DOUGHERTK ATTORNE Y Patented May 1%,

CHARLES '1. DOUGI-IEETY, 0F LEIVIOORE, CALIFORNZA, ASSIGNOB T0 F. C. DO'UG'HERTY, U33 HUNTING-TQM BEACH, CALIFGPJNIA.

DETACHA'BLE ROTARY BIT.

Application filed December 2G, 1923. Serial No. 682,669.

This invention relates to a tool for use in oil well drilling, and especially to a tool known as a rotary detachable bit.

Tn Goalinga, Bakersfield and other California oil districts, it is found that the oil bearing strata are located from 2000 to 1000 feet below the surface. The wells drilled are known as deep wells and are exceedingly costly, often requiring an expenditure of several hundred thousand dollars. The type of drill rig employed is usually the rotary as it has proven the most economical in the eistricts referred to, but even so the cost is excessive. Practically all rotary drilling rigs employa boring pipe, on the lower end of winch 1s carried a rotary bit. The pipe, together with the bit, is lowered into the well and is rotated from the surface, and as the bit rapidly wears and dulls during the drilling operation, it is necessary to pull out the boring pipe every few hours to remove the bit and to replace it with a sharp one. The time lost or required to remove the old bit, and to replace or sharpen it, is not very great when the hole or well is comparatively; shallow, but when the hole reaches a depth of 3000 to 4000 feet, it often requires a great part of the eight hour shift to merely pull the pipe for the purpose of replacing the bit or re-sharpening it. This represents a great loss of time and money, and is one of the objections to rotary drilling. There are many other objections, only a few of which will be mentioned, for instance, parting of the boring pipe at diflerent places by twisting or breakage; stripping of the threads; freezing of the pipe, due to external friction or settling of sand; loss of pipe or tools in the hole, which often necessitates a great loss of time. as fishing operations must be resorted to. which are not always successful; crooked holes are invariably produced, causing freezing of the well casing when inserted, and many other objections might be nentioned, but are hardly thought necessary.

The object of the present invention is to generally improve and simplify the construction and operation of rotary drilling rigs: accomplish this by entirely eliminattire he baring; pipe and my employing; the

well casing proper for the same purpose, and by 1 roviding a rotary bit which may be lowered down to the bottom of the casing and there attached, and similarly detached when dull so that it may be removed and re-sharpened, or replaced with a new bit, this being accomplished in a comparatively short time and without pulling the casing, thereby saving both time .and cost.

The advantages obtained by employing the casing proper for the purpose of rotating the bit, and the advantages of providine; a removable detachable bit, will more fully appear by referring to the accompanying specification and drawings, in which- Fig. 1 is a sectional view of the lower end of a well casing, showing the application of the rotary bit forming the subject matter of the present invention.

Fig. 2 is a cross-section on line 2-2, Fig. 1.

Referring to the drawings in detail and particularly to Fig. 1, A indicates the lower end of a standard form of well casing. Secured thereto by means of threads 2 is a casing shoe 3. This shoe is heavy and of larger exterior diameter than the casing. The upper end of the shoe is recessed as at 4 to formv a shoulder for the lower end of the well casing, and the inner surface of the shoe is threaded as at 5 to receive a holding nut, generally indicated at B. The lower end of the shoe is provided with an annular shoulder as indicated at 6, and the extreme lower face is bevelled and slightly flared, as shown at 7 to form a seat for a pair of drilling bits 8 and 9, hereinafter to be described.

The bits are plate-like in formation or, in other words, flat and thick. They are pivotally supported on a bolt 10 carried by the holding nut and are adapted to be extended or contracted thereby. The blades or bits 8 and 9 are longitudinally slotted as indicated at 11 to permit a predetermined amount of vertical movement with relation to the bolt 10, the reason therefor will hereinafter be described. The blades are set side by side on the bolt 10, as shown in Fig. 2, and the lower face of the holding nut B is milled out or channelled to receive the upper of bits-i Each blade is pre vided with an upper flat surface, such as or otherwise.

indicated at 12, which acts as a cam face to swing the lower ends of the blades outwardly when they reach position. They normally assume the dotted line position indicated at 8 and 9 when they are being lowered into the well, but they assume the full line position shown when extended and secured. v

Each blade is provided with a projecting lug 13 and these lugs are adapted to be received by the annular shoulder 6; that is, the lower face of each lug engages the shoulder 6, while the upper face oi each lug is .L the holding nut B;

The cutting faces of i the bits may be shaped as desired, for instance, they may be constructed to cut as an ordinary fish tail bit or they may be provided with 'dian'i'onds i heir outer ends are, however, flared so as to project slightly beyond the exterior face or the shoe 3, this being important as the cutters will therefore act to constantly undercut or roam the hole.

The holding nut B is eateriorl threaded to engage the threads 5. These threads are left-hand as the rotation of the wellcasing is right-hand, thus tending to tighten or cinch the threads 5 when in operation. The

engaged and clamped by the lower end of upper end of the holding nut is provided with a tapered socket, which in internally and right-hand threaded as indicated at 14,

and this thread is provided for the purpose of receiving the lower end of a similarly threaded rod 15, which is lowered into the well when the bit is to be removed, and similarly when a new bitis inserted. The rod 15 may be lowered into the casing or it may be suspended from an operating tool suchas shown in my copending application en titled Oil well tool operator, filed Deceinber 3, 1923, Serial No. 678,371. I prefer a bit and when removing the same, and as this tool is completely described in my cop'ending application, iurther reference th reto is thought unnecessary. It might, however, he stated that this tool may support the rod 15, and that it is capable of transmitting a turning m'm einent thereto.

For the purpose of explaining the manner in which the bit is removed, we will assume that the rod has been lowered into the casing and that the lower threaded end thereoi has been brought into engagement with 'the 'threads 14:. When this engagement is made, rotary movement is imparted to the rod 15 and the threads 14 are thus completely engaged. VVh'en engagement has been made, .iurther rotary movement is transmitted and as the threads 14- are right hand and the threads 5 left-hand, it will be seen that the holding nut will be unscrewed with relation to the threads 5. As the holding nut is being unscrewed, lugs 13 on the respective cutting bits will be released and as thebits are free to pivot on the bolt 10, it will be seen that they will swing tree of the shoulder 6 and will gradually swing inwardly to assume the dotted line positions shown. The holding nut as it is being unscrewed will finally be released with relation to the threads 5, and when completely free, it will only be necessary to pull the rod 15 out of the well, and as the holding nut and the bits are attached thereto, it is obvious that they will follow and will reach the surface in unison with the rod 15. The holding nut, togetherwith the bits, may now be removed, or the bits proper may be removed and replaced with sharp bits. The bit is thus ready to be lowered into the well casing and it is lowered to a point where the threads 5 engage. Turning movement is then transmitted to the rod 15 and the holding nut is thus screwed back into place. It will be noted. that as the holding nut, together with the bits, is lowered that the hits assume the dotted line position shown. They are, however, forced outwardly to their extended position shown in Fig. 1 when the holding nut is screwed into place as the innor taceof the nut indicated at12 will engage the cam faces 12 and will thus swing the'bits about the bolt 10 to their extended position. The extended position or" the bits is practically speaking reached before the holding nut engages the lugs 13 and the lugs will thus be securely grasped and clamped between the shoulders 6 and the lower end of the holding nut. The cutting bits are thus secured in their extended position and cannot be crowded inwardly when striking hard formations or otherwise.

The advantages of the structure here shown are many:

1. It does away with the boring pipe;

2. It eliminates tool joints such as are require; in connection with the boring pipe;

' 3. liteliminates removal of boring pipe when replacing the bit and as such reduces the time required to substantially one-halt that or ordinary practice;

4. A rig employing a tool of this character will require only about one-halt the number of men to operate it;

5. By employing the casing for the nur- 9. It reduces cost of drilling to less than one-hall. when comparison is made with ordinary rotary drilling operations;

10. Every foot of hole drilled is that much finished; r

11. It enables each string of casing to go much deeper;

12. It avoids the loss of life, so common withthe ordinary rotary drilling system;

18. The type of bit employed reams every foot of hole made;

14-. By obtaining a straight hole it re duces the side strain on the casing which in the old method causes the loss of many wells; 7 V

15. It reduces the amount of easing required;

16. It reduces water trouble, so common in crooked holes; and

17. It reduces the time. of drilling to at least one-half.

VVhen drilling with the bit and rig here shown, it is obvious that water must be delivered to the cutting edges a. the friction would otherwise burn or score them; .this is, of course, true of'any rotary bit. To elliciently deliver the water it is obvious that it is pumped through the casing in the usual manner; it then passes through a water-way formed below the socket 14, and then passes through water passages such as indicated at 16 which lead the water directly to the lower faces of the bits. The water then works upwardly around the casing and as such liberates and maintains it in a free position, thus reducing the amount of power required. to rotate the same to a minimum, and, in many cases, avoiding freezing.

It was previously stated that the cutting edges of the bits might be formed in any manner desired. I similarly wish it understood that various changes in form and pro portion may be resorted to within the scope of the appended claims, and that the materials and finish of the several parts employed may be such as the experience and judgment oi the n'ianufactruer may dictate or various uses may demand.

Having thus described my invention, what I claim and desire to secure by Letters Patent is-' 1. The combination with a well casing which is adapted to be rotated and having a shoe secured oni'ts lower end, of a holding out adapted to be screwed into the shoe and secured therein, said nut being removable with relation to the shoe through the easing, a pair of cuttingbits carried by the nut and pivotally mounted, therein to permit the bits to be projected or retracted, means for automatically projecting the bits when the holding nut is screwed into the shoe, and means whereby the bits may be locked and cla iped between the nut and shoe when projected.

2. The combination with well casing, which isadapted to be rotated, and a shoe secured on the lower end thereof, of" holding nut adapted to be received, by the shoe, a threaded connection formed between the shoe andthe nut toseeure the nut in the shoe, a pair of cutting bits carried by the nut and .pivotally mounted therein to permit the bits to be projected or retracted, an annular shoulder formed in the inner face of the shoe adjacent the lower end thereof, a lug on each cutting bit adapted to be supported by the annular shoulder, and an annular extension on the nut adapted to en gage the lugs and clamp and secure the same" with relation to the annular shoulder.

3," The combination with a well casing, which is adapted to be rotated, and a shoe secured on the lower end thereof, of a holding not adapted to be received by the shoe,

floating pin extending through the nut, a pair of cutting bits pivotally mounted on the pin, a cam member on each bit and adapted to be engaged by the nut to project the bits, and cooperating means on the shoe and on the nut to clamp and secure the bits when in projected cutting position.

4. The combination with a well casing, which is adapted to be rotated, and a shoe secured on the lower end thereof, of a holding nut adapted to be received by the shoe, a floating pin extending through the nut, a pair of cutting bits pivotally mounted 011 the pin, a cam member. on each bit and adapted to be engaged by the nut to project the bits, an annular shoulder formed on the inner face of the shoe adjacent the lower end thereof, a lug on each cutting bit adapted to be received and supported by the annular shoulder, and an annular extension on the nut adapted to engage the lugs and clamp and securethe same with relation to the an nular shoulder when the bits are projected to cutting position.

The combination with a well casing, which is adapted to be rotated, and a shoe secured on the lower end thereof, of a holding not adapted to be received by the shoe, a threaded connection formed between the shoe and the nut to secure the nut in the shoe, said nut having a slot formed in its lower end,-a floating pin projecting through the nut and extending crosswise of the slot, a pair of cutting bits extending upwardly into the slot and pivotally supported by the floating pin, a cam member on the upper end of each cutting bit and adapted to be engaged by the nut so that a swinging movement will be imparted to each bit to project the same with relation to the shoe, an annular shoulder formed on the inner face of the shoe and adj aeent the lower end thereof, the

upper face of said shoulder presentin an upwardly inc lined surface,- and the lower face of the shoulder forming an outwardly and downwardly inclined annular surface, a

projecting lug formed on each cutting bit, each lug presenting an upper and a lower face, the lower face beingdownwardly and outwardly inclined and adapted to be received by the upper face of the annular shoulder formed on the shoe, and the upper face of each lug being oppositely inclined and adapted to be engaged by a similarly inclined annular surface formed on the lower end of the holding nut, said holding nut adapted to clamp and secure the lugs on the annular shoulder of the shoe to secure the cutting bits, and an inclin t on each bit and normally engaging the lower outwardly inclined annular ace of the shoe.

6., The combination with a well casing, which is adapted to be rotated, and a shoe secured on the lower end thereof, of a holding nut adapted to be received by the shoe, a threaded connection formed between the shoe and the nut to secure the nut in the shoe, a pair of cutting bits carried by the nut and pirotally mounted therein to permit the bits to be projected or retracted, an annular shoulder formed in the inner face of the shoe adjacent the lower end thereof, a lug on each cutting bit adapted to be supported by the annular shoulder, an annular extension on the nut adapted to engage the lugs and clamp and secure the same with relation to the annular shoulder, and a threaded socket formed on the upper end of the holding nut for the reception of an operating tool.

7.-The, combination with a well casing, which is adapted to be rotated, and a shoe secured on the lower end thereof, of a holding nut adapted to be received by he shoe, athreaded connection formed between the shoe and the nut to secure the nut in the shoe, a pair of cutting bits carried by the nut pirotally mounted therein to permit the bits to be projected or'retractcd, an annular shoulder formed in the inner face of the shoe adjacent the lower end thereof, :1 lug on each cutting bit adapted to be supported by the annular shoulder, an annular extension on the nut adapted to engage the lugs and clamp and the same with relation to the annular shoulder, and a threaded socket formed on the upper end of the holding nut for the reception of an operating tool, said holding nut being provided with a central water passage, and said cutting bits being provided with water paswhich register therewith when the bits are projected to cutting position.

CHARLES T. DGUGl-IERTY. 

